For example, in a hybrid vehicle, high-voltage electric parts are installed behind a seatback of a rear seat, within a luggage compartment or underneath the luggage compartment. The high-voltage electric parts include a battery as a driving energy source. Since the battery is a heat generating part which generates heat when charged or discharged, the battery needs to be cooled to maintain its performance. The battery is desirably cooled efficiently by supplying cooling air taken in to the battery with small air passage resistance. Conventionally, for example, air inside a passenger compartment of a hybrid vehicle is taken in from a position near a rear seat and adjacent to a battery by a cooling fan, and is supplied to the battery as cooling air (e.g., Patent Literature 1).
FIG. 12 is a perspective view showing an air inlet port of a battery cooling system in Patent Literature 1. In this structure, an air inlet side passage and an air outlet passage are provided, respectively, at an upstream side and a downstream side of a cooling air passage for a battery pack installed in a luggage space behind a rear seat 101 so as to supply air inside a passenger compartment to the battery pack as cooling air. A cooling fan is provided at an intermediate portion along the length of the inlet side passage. The air inlet port 13 of the air inlet side passage is opened in an upper portion of a seat side garnish 104 disposed to a side of a seat back 102 of the rear seat 101, so that air inside the passenger compartment is taken in from the air inlet port 103.